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Current single‐junction crystalline silicon (c‐Si) solar cells are approaching their power conversion efficiency (PCE) limit. Tandem solar cells are expected to overcome such efficiency limit, with perovskite on c‐Si tandems being a promising candidate for commercialization over the next years. This work aims atdescribing the conditions that tandem cells and modules need to fulfill to successfully enter the market in 2030.We first estimate that industrial c‐Si photovoltaic modules may reach a price level of about 15 c$/W in 2030 at a PCE of 22–24%, with an expected lifetime of 30 years and an annual degradation of 0.5%. For commercial relevance, we anticipate that tandem module efficiencies need to be increased to reach around 30%, while matching lifetime and degradation rate of c‐Si modules. Provided these conditions, we find that these tandem modules could then have a cost bonus of around 5–10 c$/W compared to c‐Si modules for reaching equal levelized cost of energyvalues. Tandem modules with 30% power conversion efficiency in 2030 could have a price premium of around 5–10 c$/W and still reach the same levelized cost of energy values as PV systems using standard c‐Si modules. However, to achieve this, such tandem modules need to match the lifetime and degradation rate of c‐Si modules with similar bankability conditions.
IPVF's PV technology vision for 2030
Lars Oberbeck
| Katherine Alvino
| Baljeet Goraya
| Marie Jubault
Total Gas, Renewables & Power, 2 place Jean
Millier, Paris La Défense Cedex, 92078, France
Institut Photovoltaïque d'Ile-de-France,
18 Boulevard Thomas Gobert, Palaiseau,
91120, France
EDF R&D, Group Technologies Solaires",
18 Boulevard Thomas Gobert, Palaiseau,
91120, France
Fraunhofer ISE, Heidenhofstr. 2, Freiburg,
79110, Germany
Lars Oberbeck, PhD, Total Gas, Renewables &
Power, 2 place Jean Millier, Paris La Défense
Cedex, 92078, France.
Present address
Baljeet Goraya, Fraunhofer ISE, Heidenhofstr.
2, Freiburg, 79110, Germany
Funding information
Programmed'Investissementd'Avenir, Grant/
Award Number: ANR-IEED-002-01
Current single-junction crystalline silicon (c-Si) solar cells are approaching their power
conversion efficiency (PCE) limit. Tandem solar cells are expected to overcome such
efficiency limit, with perovskite on c-Si tandems being a promising candidate for
commercialization over the next years. This work aims atdescribing the conditions
that tandem cells and modules need to fulfill to successfully enter the market in
2030.We first estimate that industrial c-Si photovoltaic modules may reach a price
level of about 15 c$/W in 2030 at a PCE of 2224%, with an expected lifetime of
30 years and an annual degradation of 0.5%. For commercial relevance, we anticipate
that tandem module efficiencies need to be increased to reach around 30%, while
matching lifetime and degradation rate of c-Si modules. Provided these conditions,
we find that these tandem modules could then have a cost bonus of around 510 c
$/W compared to c-Si modules for reaching equal levelized cost of energyvalues.
levelized cost of energy (LCOE), perovskites, power conversion efficiency (PCE), tandem
Photovoltaic (PV) energy generation systems have reached annual
installation volumes of >100 GW and a cumulative installation volume
of >500 GW at the end of 2018. The market is dominated by
crystalline silicon (c-Si) technologies that have seen a tremendous cost
reduction in recent years and a significant increase in power conver-
sion efficiency (PCE), making the technology competitive in terms of
levelized cost of energy (LCOE) in many regions of the world. How-
ever, the PCE of single-junction c-Si PV is approaching its perceived
practical limit, driving the attention towards new technologies that will
enable PCEs higher than 30% while reducing the cost of PV systems.
At the COP21 climate change conference in Paris in 2015, the
InstitutPhotovoltaïqued'Ile-de-France (IPVF) published a position
paper on efforts required in PV to fight climate change and gave itself
an objective of 3030-30: PV module efficiency of >30% at a price
of <30c$/W by 2030, to be achieved using tandem PV modules, with
the support of 10 representatives of major international PV research
Four years later, in this paper we review our PV market
vision for the year 2030 and our strategic view on the tandem PV
module technologies and their market introduction. We review exis-
ting PV technologies, markets and costs and outline boundary condi-
tions under which tandem PV modules could successfully be
introduced in the market.
To assess the competitiveness of tandem PV modules vs. c-Si
modules in 2030, we use an iso-LCOE approach, i.e. we determine
the price difference between tandem and c-Si modules that results
in the same LCOE value, dependent on the lifetime, degradation,
financing conditions etc. of tandem modules. Figure 1 outlines the
approach: from the expected cumulative PV installation in 2030, we
determine a possible c-Si module price range from the learning
curve. As this range will be rather broad, also depending on the
learning rate used for the extrapolation, we use a comparison with
module materials cost data for 2030 and current module market
prices to eliminate the very low and high price ranges (i.e. below
materials cost or above current market price). This c-Si module price
Received: 3 December 2019 Revised: 27 April 2020 Accepted: 2 June 2020
DOI: 10.1002/pip.3305
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,
provided the original work is properly cited.
© 2020 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd
Prog Photovolt Res Appl. 2020;18. 1
value is then used together with the extrapolated module efficiency
to 2030 in an LCOE calculation for two different PV system sizes
and locations to determine the costbonus/malus of tandem vs. c-Si
modules, as an indicator of the competitiveness of tandem modules
in the PV market in 2030.
The PV module market is dominated by c-Si technology with a market
share of about 95%, whereas thin-film technology, mainly cadmium
telluride (CdTe) and copper indium gallium selenide (CIGS), has a
FIGURE 1 Approach used to determine the
costbonus or malus (i.e. competitiveness) of
tandem vs. c-Si PV modules at iso-LCOE for 2030
FIGURE 2 Historical evolution of mainstream
(Al-BSF/PERC) industrial crystalline silicon solar
cell and module power conversion efficiencies
(from refs. [6, 8, 10] As well as internal data) and
extrapolation towards 2030, using the Pearl-Reed
to take the practical efficiency limit of
c-Si solar cells of 27% (low scenario) and the
theoretical limit of 29.4% (high scenario),
respectively, into account. ITRPV expectations for
IBC cells are shown for comparison
figure can be viewed at]
market share of about 5%.
While the theoretical PCE limit of c-Si
solar cells is 29.4%,
the record c-Si solar cell efficiency to date was
achieved by Kaneka for an Interdigitated Back-Contact Silicon
Heterojunction (IBC-SHJ) solar cell with 26.7%.
Best production cell
efficiencies are reached by SunPower with about 25% for IBC tech-
and mainstream c-Si Passivated Emitter and Rear Cell (PERC)
in production reaches ca. 22.2%.
However, c-Si solar cells are approaching the practical PCE limit
which is thought to be in the 27% efficiency range (see e.g.
). Aver-
age industrial solar cell and module efficiencies have increased over
the last years by 0.40.6% abs. per year.
Figure 2 shows historical
industrial mainstream Aluminum Back-Surface-Field (Al-BSF) and
PERC cell and module efficiency data extrapolated towards 2030,
applying the Pearl-Reed function
and their respective upper solar cell
efficiency limits of 27% and 29.4%. The Pearl-Reed curve (Equation 1)
presents an s-shaped form that describes an accelerated growth at
the beginning, followed by a slowing down after reaching half of the
possible improvement:
1+aebt ð1Þ
with n(t) = time-dependent efficiency, L = upper limit of n(t), a = loca-
tion coefficient and b = shape coefficient.
Module power conversion efficiencies were calculated from
the respective cell efficiencies, using cell-to-module (CTM) power
ratios from the International Technology Roadmap for Photovoltaic
In 2025, average industrial cell efficiencies of ca. 24%
can be expected, and in 2030 values of ca. 25%. Average module
efficiencies of around 22% can be anticipated for 2025, further
increasing in 2030 to around 23%, approaching the practical effi-
ciency limit. For comparison, we also show IBC cell efficiencies that
will reach approximately 26% in 2030, according to expectations
from ITRPV.
Besides efficiency, the lifetime of c-Si PV modules is a critical
parameter. Manufacturers today typically give a performance
warranty with a specified power output value after 25 years for glass-
backsheet modules and 30 years for glassglass modules. The
module power warranty has increased over time from originally
5 years in the 1980 s
and is expected to reach 30 years in general
from 2022 onwards.
At the end of their life (or after early failures), it is mandatory in
the European Union
(and increasingly required in other regions of
the world as well) that PV modulesare recycled. Due to small volumes,
dedicated PV recycling is almost non-existent as of today, but
these modules are being processed on existing recycling lines for
other consumer products. While today, mainly for c-Si modules, only
aluminum frames and glass are re-used and encapsulants and silicon
cells are incinerated, it can be expected that in the future more
advanced recycling schemes will be implemented that maximize
the value of recycled material and minimize the ecological footprint of
the PV modules. For an overview of PV module recycling see
e.g. ref. [14].
In order to further increase cell and module efficiencies and thereby
leveraging balance of system (BOS) costs, tandem solar cells and
modulesare expected to be introduced in the market from around
2023 onwards.
Such tandem solar cellshave a theoretical efficiency
limit of >40%.
Various materials combinations for tandem cells are
currently under investigation, the most prominent being perovskites
on c-Si,
III-V on c-Si,
perovskite on perovskite,
perovskite on CIGS
and CIGS on Si
in 2-terminal (2 T), 3 T or 4 T
configurations. Both 2 T and 4 T configurations show advantages and
disadvantages: 2 T tandem cells benefit from easier, less costly mod-
ule integration using established production technologies, whereas
4 T cells maximize power output without the need of current
matching between the two sub-cells, but require non-standard mod-
ule integration of the top and bottom cells. Differences in power out-
put between 2 T and 4 T tandem cells have been investigated by
various authors and are expected to be between 12%
and around
depending on mounting conditions and location.
In the case of III-V, single-junction solar cells achieve high effi-
ciencies of currently up to 29.1%
and tandem cells achieve 32.8%
(GaInAsP/GaAs, 2 T),
and 32.8% for GaAs on c-Si (4 T).
there is a critical cost issue withIII-V materialsthat is being currently
addressed e.g. by developing lower-cost deposition methods such as
hydride vapor phase epitaxy (HVPE).
On the other hand, being at a lower level of maturity, perovskite
tandem solar cells have already reached a PCE of 28.0% in a 2 T
thereby surpassing all single-junction c-Si solar cells,
with the potential of having low costs.
For a 4 T configuration, a
practical implementation of combining a bifacial c-Si bottom cell with
a perovskite top cell has recently been shown by ECN/Solliance with
a cell efficiency of 30.2%.
Note however that this is the so-called
bifacial-equivalent efficiencythat assumes 20% of standard irradi-
ance also impinging onto the rear side of the bifacial cell and that
must not be confused with the power conversion efficiency PCE.
The PCE of this cell is in the 26% range. While upscaling and
stability issues of perovskites are still challenging, continuous progress
is under way.
Bifacial solar cells and modules can increase the power output by
up to 30% in an ideal case compared to monofacial cells and
but performance strongly depends on the albedo and
use case. Three-terminal and 4 T tandem modules can benefit from
bifacial bottom solar cells, whereas bifacial 2 T tandems are less
favorable due to current matching issues associated with varying
current generation in bifacial bottom cells from varying rear-side
illumination conditions.
The requirement for recycling of PV modules, as mentioned in the
previous section, also holds for novel technologies that are introduced
in the market. Recycling studies are therefore needed to follow the
development of multijunction cells and modules. In the case of perov-
skite on c-Si tandem modules, first investigations on the recycling of
perovskite thin-film test cells have been carried out with the intention
of re-using the transparent conductive oxide coated glass (as the
highest cost component) and recycling the Pb-containing perovskite
layer, see e.g. refs. [30, 31]. These studies seem to bode well for the
future recycling of commercial perovskite on c-Si tandem modules.
Addressing the evolution of the PV market, it is obvious that histori-
cally the market growth has repeatedly been underestimated so far,
see e.g. ref. [32]. Recent estimates predict a cumulative installed PV
capacity in 2030 ranging from 1.29 TW
to 5.01 TW,
see Table 1.
Applying IEA current policies and the Shell sky scenario as the
lower and upper estimates for cumulative shipments, we use the
learning curve of PV modules to extract a target range of PV module
prices that can be expected in 2030, see Figure 3. The learning curve
can be expressed as
with C (qt) = quantity-dependent module price, q0 = accumulated
module shipments in year 0, t = time, qt = accumulated shipments in
year t and b = constant.
The learning rate (LR)which describes the
price change with a doubling of cumulative shipments is
LR = 12bð3Þ
The learning curve describes the price reduction per watt peak of
PV modules with increasing cumulative shipments. This price reduc-
tion mainly results from economy of scale and only to a smaller extent
from an increase in the PCE.
Historically, the learning rate is about
24% for the years of 1976 to 2018. Considering specifically recent
years when mass production of PV modules started, the authors
find for the period from 2008 to 2018 a learning rate of 38.6%. At
the beginning of 2019, average c-Si PV module spot market prices
were around $0.21/W to $0.27/W, depending on the technology
and region.
From the extrapolation of the learning and PV module efficiency
curves, we conclude that c-Si modulesmay reach a price rangeof
$0.06/W to $0.34/W in 2030, depending on cumulative shipments
and learning rate, with industry average module PCEsof about 23%.
The lower limit of the price range results from applying the high LR of
38.6% from 2008 onwards, while the higher limit is determined by the
extrapolation of historical data with a LR of 24%. The application of
the historical LR of 24% to the 2018 module price data point gives
values of $0.11/W to $0.19/W in 2030, depending on the cumulative
PV installation scenario. While there is good reason to assume that a
module price of $0.34/W is too high, given that 2019 values are
already significantly lower, it is desirable to further narrow down the
broad range by estimating the material costs of a PV module in 2030
as a lower limit to the module price. Note that for the PV industry to
be financially self-sustaining, the long-term operating profit margin
should be around 15%, see e.g. ref. [39], i.e. a module price of 15 c
$/W would correspond to a cost of ca. 13 c$/W.
We perform a bottom-up module materials cost assessment for a
60-cell glass-backsheet monocrystalline Si PERC module that can be
used as a lower boundary for module prices in 2030. We use a detailed
PV module cost model that has been developed within Total for this
simplified calculation that takes into account wafer costs, costs of silver
and aluminum metallization pastes and of screens used in screen-
printing metallization as well as module material costs. Labor costs,
depreciation and other costs are not considered. As materials represent
about 80% of the module and cell conversion costs, this leads us to a
reasonable assumption for a lower limit to future PV module costs.
Key assumptions: (based on internal data, ITRPV
and PV Pulse
For Q4/2018: 175 μm wafer thickness, 88 μm kerf loss; 22% cell
efficiency; Ag (130 mg per cell), Al paste (950 mg per cell) and
screen costs
For 2030 moderate scenario: 120 μm wafer thickness, 60 μm kerf
loss; 24% cell efficiency; Ag (70 mg per cell), Al paste (700 mg per
cell) and screen costs; 4.6% module materials cost reduction per
year (calculated from ref. [40])
For 2030 aggressive scenario: 100 μm wafer thickness, 50 μm kerf
loss; 27% cell efficiency; Ag (55 mg per cell), Al paste (600 mg per
cell) and screen costs; 4.6% module materials cost reduction per
year, add. -20% backsheet and frame costs
As shown in Table 2, we consider two scenarios for 2030, a mod-
erate and an aggressive cost scenario which differ in cell efficiency,
wafer thickness and kerf loss as well as paste consumption. The
TABLE 1 Cumulative PV module installation volumes in 2030
from various sources
Cumulative installation
in 2030 [TW]
IEA current policies
IEA new policies
IRENA 2017
IEA sustainable development
ITRPV high
Shell sky scenario
Abbreviation: BNEF, Bloomberg New Energy Finance; IEA, International
Energy Agency; IRENA, International Renewable Energy Agency.
applied values are variations of the expectations in ITRPV's
Note that a 24% cell efficiency in 2030 should be at the
lower end of future industrial solar cell PCEs and is expected to be
achieved by improved PERC solar cells, whereas an efficiency of 27%
would require a high-end single junction c-Si solar cell which, from
today's perspective, could be realized by IBC-SHJ technology. We
estimated that the module materials cost value in 2030 is driven by
the rate of cost reduction of module materials such as glass,
encapsulant, backsheet etc. We assume this annual cost reduction to
be 4.6%, based on calculations from PV Pulse data for recent years.
The module materials cost value for Q4/2018 is shown for compari-
son and as a sanity check for our cost model and assumptions. Given
current average monocrystalline silicon PERC module prices of around
27 c$/W displayed at PVinsights,
our value of 18.9 c$/W for mod-
ule material costs seems appropriate.
For the year 2030, our bottom-up module material costs assess-
ment results in 10.3 and 8.0 c$/W for the moderate and aggressive
scenario, respectively. Therefore, we have color-coded in Figure 3 the
range of PV module prices and cumulative shipment values that could
be expected in 2030 depending on the likelihood of occurrence: the
range of module prices below 8 c$/W is shown in red, since we
assume that they are unlikely to be achieved with current module
technologies. The range above 10.3 c$/W is colored in green, indicat-
ing that these values are more likely to be achieved given our mate-
rials costs assessment. The range in-between is shown in yellow to
indicate an intermediate likelihood of being realized. Note that our
cost assessment assumes that current module technology for glass-
backsheet modules with encapsulants and tabbing/stringing will con-
tinue to be used. The development of novel module technologies,
e.g. encapsulant-free modules,
could help in further reducing
manufacturing cost, increasing energy yield over module lifetime and
facilitating recycling.
Based on our expectations for module efficiency and cost in 2030, we
calculate technical LCOE values (without taxes) for two locations,
Southern France with an energy yield of 1,575 kWh/kWp/a and
Northern Europe with 1,025 kWh/kWp/a,
see Table 3. For the cal-
culation of LCOE for new plants, we use the net present value method
to arrive at the ratio of the discounted lifecycle costs over the
discounted lifetime energy generation of the plant.
We find ranges
of LCOE values for both large- (1 MWp) and small-scale (100 kWp)
PV installations,resulting from the different module cost and PCE
input data as well as ranges of BOS costs that we obtain by applying a
cost reduction methodology to 2050 as described in ref. [37]. The
resulting CAPEX (i.e. sum of module and BOS costs) is found to be in
close agreement to the estimated CAPEX in 2030 by IHS Markit.
comparison with LCOE values from IHS Markit
shows good robust-
ness of the results, given the difference in tax consideration. Note
that the assumed module efficiencies of 22.2% and 25.2% correspond
to cell efficiencies of 24 and 27%, respectively, based on CTM
assumptions by ITRPV.
Our main objective in calculating LCOE values is to determine the
additional cost that can be allowed for 30% efficient tandem modules,
compared to c-Si modules with efficiencies of 22.2% and 25.2%. For
this, we use varied scenariosfor obtaining the same LCOE values than
FIGURE 3 Learning curve of average PV
module price as a function of cumulative
shipments, incl. extrapolation to expected
cumulative shipment values in 2030 from various
sources (see Table 1) using different learning
rates: IPVF extrapolation of PV learning rates
historical (1976 to 2018: 24%) and recent trend
(2008 to 2018: 38.6%). The colored areas indicate
the likelihood of achieving respective price values
from a bottom-up materials cost estimate (see
following section) and the grey area marks
module prices that are higher than today's values
[Colour figure can be viewed at]
TABLE 2 Bottom-up materials cost estimation for a 60-cell glass-backsheet monocrystalline siliconPERC module. Cost modelling is based on
a Total-internal cost model as well as material costs data from PV Pulse
Q4/2018 2030 moderate scenario 2030 aggressive scenario
Wafer (2019 c$/W) 7.0 4.2 2.9
Cell materials (2019 c$/W) 2.7 1.5 1.1
Module materials (2019 c$/W) 9.2 4.7 3.9
Total cost of materials (2019 c$/W) 18.9 10.3 8.0
c-Si modules in 2030 with a lifetime of 30 years and an annual degra-
dation of 0.5%, values in accordance to those from ITRPV.
investigate the influence of higher WACC rates, shorter lifetime and
higher annual degradation rates of the tandem module on the tandem
module cost bonus. Results for small- and large-scale systems located
in outhern France are shown in Figure 4. Due to the higher relative
BOS costs, effects on the tandem module costs are more pronounced
for small-scale applications.
As a result, a cost bonus of up to 12c$/W can be observed if the
tandem module matches the c-Si module's lifetime and degradation
rate, i.e. the tandem module cost can be 12 c$/W higher than the cost
of the 22.2% efficient c-Si module for achieving the same LCOE value.
Naturally, this cost bonus decreases (and can also turn into a cost
malus) with decreasing lifetime and increasing annual efficiency degra-
dation of the system. The situation is generally worsened for large-
scale PV installations with lower relative BOS costs and compared
against a higher reference module efficiency of 25.2%.
Our calculations emphasize as well the importance of achieving a
high reliability of the tandem PV module: for a 30-year lifetime and
low to moderate degradation rates of 0.5 or 0.75%/a, tandem mod-
ules have a cost bonus of 2 to 12 c$/W, whereas for a reduced
lifetime of 25 years and a higher annual degradation of 1%, a malus of
up to 9 c$/W can be observed, i.e. such less reliable tandem module
would need to have 9 c$/W lower cost to achieve the same LCOE as
the reference c-Si PV module.
Project financing, represented by the WACC rates, has an even
more pronounced influence on the financial viability of using tandem
modules, see Figure 4: At a WACC of +2% abs. compared to the cal-
culation for c-Si modules, the tandem module cost bonus previously
obtained using the same WACC turns into a malus, both for small-
and large-scale PV projects and across all degradation rates. Thus,
obtaining the same financing conditions for PV projects with tandem
modules as for projects applying standard modules is therefore of
utmost importance, highlighting the need for high lifetime and reliabil-
ity of tandem modules in order to gain the same level of bankability as
for c-Si modules.
Our results show that c-Si modules may reach a price of ca. 15 c$/W
or lessin 2030, agreeing with expectations of other authors.
At that
TABLE 3 Expected technical (without taxes) LCOE values in 2030 for small- and large-scale PV systems in two different locations using an
LCOE model developed within IPVF
and comparison with literature data (ref. [44], incl. taxes). WACC: Weighted average cost of capital. Key
assumptions: Annual degradation 0.5%, lifetime 30 years
Small-scale PV (size: 100kWp) Large-scale PV (size: 1 MWp)
LCOE southern France 1,575
kWh/kWp/a (c$/kWh)
10.411.1 (comparison value: 12.9,
) 2.83.3 (comparison value: 4.1,
LCOE northern Europe 1,025
kWh/kWp/a (c$/kWh)
16.017.1 (comparison value: 16.2,
) 4.75.4 (comparison value: 7.1,
Module cost (c$/W) 10/15 10/15
Module PCE (%) 22.2/25.2 22.2/25.2
WACC (real in %)
6 4/5 (France/Sweden)
CAPEXcalculated ($/kW) 1,5901,690 500580
OPEX (as % of CAPEX)
2.5 2.5
FIGURE 4 The tandem module cost
that results in the same LCOE value that
is achieved using a c-Si reference module
depends both on the lifetime (30 vs.
25 years) and the annual PCE degradation
(0.5%/a, 0.75%/a, 1%/a) of the system
using tandem modules, as well as the
reference module PCE (22.2% vs. 25.2%),
but also strongly on the financing costs
(WACC). Large- and small-scale PV
installations differ in BOS costs and
WACC rates. The lifetime of the
reference module is 30 years, the annual
system degradation 0.5%, the efficiency
of the tandem module is 30% and the
location southern France. Further details
can be found in Table 3 [Colour figure can
be viewed at]
time, module PCEs of 2224% are expected to be standard in indus-
trial production, possibly a maximum of ca. 25% if IBC-SHJ solar cells
can be industrialized. Such modules are expected to have a lifetime of
30 years at an annual PCE degradation of 0.5%. Further efficiency
increases of single-junction c-Si solar cells seem unlikely given their
theoretical efficiency limit of 29.4%.
However, further cost reduction might be possible if novel mod-
ule concepts with a different bill of materials (BOM) were introduced.
To overcome the PCE limit of c-Si modules in production, perovskite
on c-Si tandem modules currently seem to be the most promising can-
didate. For commercial relevance, it is expected that tandem cell and
module efficiencies will need to be further increased to reach ca. 30%
module PCE, and that such modules need to match lifetime and degra-
dation rate of c-Si modules in order to gain bankability. These tandem
modules could then have a cost bonus of around 510 c$/W com-
pared to c-Si modules in our example for an installation in Southern
France in 2030 to reach equal LCOE values, i.e. the tandem module
price could be around 2025 c$/W. If bankability remains lower than
for standard modules, project financing conditions are not expected
to be in favor of tandem modules which would have a cost malus in
LCOE calculations, meaning that they would need to have even lower
costs than c-Si modules.
For a market introduction of tandem PV modules, we can distin-
guish between two different cases: small-scale PV applications, in par-
ticular residential, and large-scale PV applications. The criteria that
need to be met for a successful market introduction are different for
the two cases. For residential applications, higher module efficiencies
at comparable or better PV module lifetime and degradation rates are
key, qualifying the tandem module as a premium product. Here, expe-
rience with current high-efficiency c-Si IBC and SHJ modules shows
that customers may pay a high-efficiency premiummodule price that
goes beyond the benefits of high-efficiency modules in LCOE calcula-
tions. For large-scale PV applications, bankability and LCOE advantage
(which takes e.g. cost, efficiency, degradation and lifetime of the mod-
ule into account) are the most important criteria. In both cases, tan-
dem modules should come as a plug-insolution for conventional
modules, i.e. they should not require modifications of existing BOS
components. Note that module recyclability or other measures for
waste reduction are mandatory requirements for all cases.
We anticipate that perovskite on c-Si tandem modules, which can
build upon a > 100 GW c-Si module production base, might first be
deployed in constrained area markets as a premium product, compet-
ing with SHJ and IBC premium c-Si modules. Such an introduction of
the novel material perovskite in the PV market could then help in
decreasing the hurdles for bankability associated with technology risks
of novel materials. Note that there can also be specific incentives for
the market introduction of a novel high-efficiency technology (such as
China's Top Runner program currently
) that can facilitate gaining
extended field experience to demonstrate module performance, and
in particular reliability, for subsequent large-scale deployment.
Current and future work at IPVF therefore focuses on the devel-
opment of low-cost, high-efficiency tandem modules mainly using
perovskite on c-Si, but also alternative technologies based on
combinations with III-V materials.
While we have achieved first
promising results for perovskite on c-Si tandem cells,
we are com-
mitted to demonstrate a tandem cell with a PCE of >30% that can be
commercialized before 2030, with the help of national and interna-
tional academic and industrial collaborations.
The authors thank N.-P. Harder, A. Ristow, E. Drahi, D. Verstraeten,
D. Lincot, E. Sandré, P. Uhlig and M. Woodhouse for helpful
discussions. This project has been supported by the French
Government in the frame of the program of investment for the future
(Programmed'Investissementd'Avenir - ANR-IEED-002-01).
There are no conflicts to declare.
Katherine Alvino
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... Figure 9a shows the PV system power for the various acceleration forms, as shown in Figure 7a. Based on new photovoltaic cell technologies [56,57], the PV can generate 9W as its maximum energy for the best irradiation factor. erating electricity. ...
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Technical Report
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The study compares the present costs for conversion of different energy forms into electricity and gives a prognosis for the further cost development up to 2035. The study analyzes both the levelized cost of electricity (LCOE) from renewables as well as from conventional energy technologies. They present comparative figures for new power plants constructed in Germany, which are based on solar, wind energy and biogas as well as brown coal, hard coal and gas.
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Multi-junction all-perovskite tandem solar cells are a promising choice for next-generation solar cells with high efficiency and low fabrication cost. However, the lack of high-quality low-bandgap perovskite absorber layers seriously hampers the development of efficient and stable two-terminal monolithic all-perovskite tandem solar cells. Here, we report a bulk-passivation strategy via incorporation of chlorine, to enlarge grains and reduce electronic disorder in mixed tin–lead low-bandgap (~1.25 eV) perovskite absorber layers. This enables the fabrication of efficient low-bandgap perovskite solar cells using thick absorber layers (~750 nm), which is a requisite for efficient tandem solar cells. Such improvement enables the fabrication of two-terminal all-perovskite tandem solar cells with a champion power conversion efficiency of 21% and steady-state efficiency of 20.7%. The efficiency is retained to 85% of its initial performance after 80 h of operation under continuous illumination. © 2018, The Author(s), under exclusive licence to Springer Nature Limited.
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In this work, the fabrication of MoOx-free semitransparent perovskite solar cells (PSC) with Power Conversion Efficiencies (PCE) up to 15.7% is reported. Firstly, opaque PSCs up to 19.7% were fabricated. Then, the rear metal contact was replaced by a highly transparent and conductive indium tin oxide (ITO) film, directly sputtered onto the hole selective layer, without any protective layer between Spiro-OMeTAD and rear ITO. To the best of our knowledge, this corresponds to the most efficient buffer layer-free semitransparent PSC ever reported. Using time-resolved photoluminescence (TRPL) technique on both sides of the semitransparent PSC, Spiro-OMeTAD/perovskite and perovskite/TiO2 interfaces were compared, confirming the great quality of Spiro-OMeTAD/perovskite interface, even after damage-less ITO sputtering, where degradation phenomena result less important than for perovskite/TiO2 one. Finally, a 4-terminal tandem was built combining semitransparent PSC with a commercially-available Aluminium Back Surface Field (Al-BSF) silicon wafer. That silicon wafer presents PCE = 19.52% (18.53% after being reduced to cell size), and 5.75% once filtered, to generate an overall 4 T tandem efficiency of 21.18% in combination with our champion large semitransparent PSC of 15.43%. It means an absolute increase of 1.66% over the original silicon wafer efficiency and a 2.65% over the cut Si cell.
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Photovoltaic conversion efficiencies of 32.6 ± 1.4% under the AM1.5 G173 global spectrum, and 35.5% ± 1.2% at 38-suns concentration under the direct spectrum, are demonstrated for a monolithic, dual-junction 1.7/1.1 eV solar cell. The tandem cell consists of a 1.7 eV GaInAsP top-junction grown lattice-matched to a GaAs substrate, followed by a metamorphic 1.1 eV GaInAs junction grown on a transparent, compositionally graded metamorphic AlGaInAs buffer. This bandgap combination is much closer to the dual-junction optimum and offers headroom for absolute 3% improvement in efficiency, in comparison to the incumbent lattice-matched GaInP/GaAs (∼1.86/1.41 eV) solar cells. The challenge of growing a high-quality 1.7 eV GaInAsP solar cell is the propensity for phase separation in the GaInAsP alloy. The challenge of lattice-mismatched GaInAs solar cell growth is that it requires minimizing the residual dislocation density during the growth of a transparent compositionally graded buffer to enable efficient metamorphic tandem cell integration. Transmission electron microscopy reveals relatively weak composition fluctuation present in the 1.7 eV GaInAsP alloy, attained through growth control. The threading dislocation density of the GaInAs junction is ∼1 × 10⁶ cm⁻², as determined from cathodoluminescence measurements, highlighting the quality of the graded buffer. These material advances have enabled the performance of both junctions to reach over 80% of their Shockley-Queisser limiting efficiencies, with both the subcells demonstrating a bandgap-voltage offset, WOC (=Eg/q-VOC), of ∼0.39 V.
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since July 2018 are reviewed.
High-efficiency back-contact heterojunction crystalline Si (c-Si) solar cells with record-breaking conversion efficiencies of 26.7% for cells and 24.5% for modules are reported. The importance of thin-film Si solar cell technology for heterojunction c-Si solar cells with amorphous Si passivation layers in improving conversion efficiency and reducing production cost is demonstrated. Our attempts to reduce the production cost of a heterojunction c-Si solar cell by applying a SiO x layer prepared by a plasma-enhanced CVD method are presented. The characteristics of heterojunction c-Si solar cells are clarified by comparing them with those of practical homojunction solar cells, and crucial targets for industrialization of back-contact heterojunction c-Si solar cells are discussed. Owing to the recent improvement of c-Si solar cells and perovskite solar cells, conversion efficiencies over 30% have become a realistic target by using a two-terminal tandem structure with a heterojunction c-Si solar cell and a perovskite solar cell.
Metal halide perovskite semiconductors possess excellent optoelectronic properties, allowing them to reach high solar cell performances. They have tunable bandgaps and can be rapidly and cheaply deposited from low-cost precursors, making them ideal candidate materials for tandem solar cells, either by using perovskites as the wide-bandgap top cell paired with low-bandgap silicon or copper indium diselenide bottom cells or by using both wide- and small-bandgap perovskite semiconductors to make all-perovskite tandem solar cells. This Review highlights the unique potential of perovskite tandem solar cells to reach solar-to-electricity conversion efficiencies far above those of single-junction solar cells at low costs. We discuss the recent developments in perovskite-based tandem fabrication, and detail directions for future research to take this technology beyond the proof-of-concept stage.
Low photovoltaic module costs imply that increasing the energy yield per module area is now a priority. We argue that modules harvesting sunlight from both sides will strongly penetrate the market but that more field data, better simulation tools and international measurement standards are needed to overcome perceived investment risks.
Recently, metal halide perovskite photovoltaics (PV) are marching toward commercialization. The possibility for perovskite absorbers to be incorporated into multi-junction solar cells is also being discussed, which suggests alternative market entry. Although intensive investigations are being made on their technical feasibility, serious analysis on the cost of perovskite-based tandem modules is lacking. The levelized cost of electricity (LCOE) of solar modules is often used to evaluate technoeconomic competitiveness. Here, we performed a detailed cost analysis on two perovskite-based tandem modules (the perovskite/c-silicon and the perovskite/perovskite tandem module) compared with standard multi-crystalline silicon and single-junction perovskite solar cells. We found that perovskite PVs (both single junction and multi-junction) are competitive in the context of LCOE if the module lifetime is comparable with that of c-silicon solar cells. This encourages further efforts to push perovskite tandem modules onto the market in the future.