Full steam ahead for Photovoltaics in US homes?

Mark Bolinger, Galen Barbose and Ryan Wiser

The US congress finally voted to extend and enhance tax credits for some renewables, notably solar. But will this provide the boost that the residential sector in the USA has been waiting for? Mark Bolinger, Galen Barbose and Ryan Wiser, of the Lawrence Berkeley National Laboratory, consider the implications of the legislation for existing incentives.

In October 2008, the United States Congress extended both the residential and commercial solar investment tax credits (ITCs) for an unprecedented 8 years. It also lifted the US$2,000 cap on the residential credit, removed the prohibition on utility use of the commercial credit, and eliminated restrictions on the use of both credits in conjunction with the Alternative Minimum Tax.

These significant changes, which apply to systems placed in service on or after 1 January 2009, will increase the value of the solar credits for residential system owners in particular, and are likely – in conjunction with state, local, and utility rebate programmes targeting solar – to spur significant growth in residential, commercial, and utility-scale photovoltaic (PV) installations in the years ahead.

Significantly, there are three areas in which removal of the US$2,000 cap (on the residential ITC) will have significant implications for PV rebate programme administrators, PV system owners, and the PV industry:

  • Reduced rebate levels to at least partially compensate for the more-valuable ITC;
  • Reconsideration of complementary low-interest loan programmes – “subsidised energy financing”;
  • Third-party financing.

State, local, and utility PV programmes – effect of rebates

With the exception of the smallest systems, which have not been impacted by the US$2,000 cap on the residential ITC, most residential PV systems installed – starting in 2009 – will realise significant additional value from the elimination of the ITC cap. State, local, and utility PV programme administrators may, in turn, wish to ratchet down the size of the rebates they offer, in order to stretch fixed programme budgets and avoid over-stimulating the market. Indeed, at least three major PV programs have already reduced their incentive levels for residential PV as a result of the ITC cap removal, and others are considering the same.

Working with the 2008 residential rebates (i.e. prior to the elimination of the ITC cap) and assuming that they were set at a level that provided the desired amount of support to the residential sector, figure 1 shows the maximum amount by which these rebate levels could – in theory – be reduced starting in 2009 once the ITC cap is gone; this assumes that system owners are not left any worse off than they are now on an after-tax basis – under current rebate levels and the US$2,000 ITC cap. Note that figure 1 assumes that rebates are non-taxable, which is the case if the rebate is provided through a “utility programme” (see details of the original report, noted at the end of the article, for a discussion of what constitutes a “utility programme”).

This tax distinction is important because, if the rebates are considered to be federally taxable income, then a rebate recipient can claim the 30% ITC on the full cost (or “tax credit basis”) of the system. If, however, the rebates are not taxable income, then the rebate recipient must reduce, by the amount of the rebate, the tax credit basis to which the federal ITC applies. The magnitudes shown in figure 1 would, therefore, be somewhat larger if taxable rebates were assumed.

For non-taxable rebates, the magnitude of the potential rebate reduction depends only on the starting rebate level as well as the size and cost of the system (figure 1 assumes that per-unit installed costs decline along a concave curve from US$10.50/W at 0.5 kW to US$7.75/W at 10 kW). As shown, small systems (0.5 kW–2 kW) cannot withstand as much of a rebate reduction as can larger systems, because smaller systems will benefit less from the removal of the US$2,000 cap (i.e. they were not as impacted by the cap in the first place). Above roughly 3 kW, however, the curves more or less level out, revealing that a rebate currently set at US$1/W could be reduced by as much as US$2.5/W (in theory, going negative) without leaving the system owner any worse off on an after-tax basis.

Meanwhile, starting with a non-taxable rebate of US$4/W, the size of the potential reduction is smaller, at roughly US$1.25/W. Falling in between these two extremes are starting rebate levels of US$2/W and US$3/W. This rank-ordering makes intuitive sense: a small non-taxable rebate reduces the project's “tax credit basis” by less than a large non-taxable rebate, which means that the removal of the US$2,000 ITC cap provides greater benefit to a system receiving a smaller non-taxable rebate. Such a system can, in theory, therefore withstand a larger reduction in the size of the rebate.

While the idea of shifting part of the cost of supporting residential PV to the Federal Government must look quite appealing to many State Utility and local PV programme managers, there are, nevertheless, several factors that programme managers may wish to consider when deciding whether – or by how much – to reduce residential rebate levels. These include:

  • PV system owners may have to wait up to a year or more (depending on how early in the year the system is installed) before they file their annual tax returns and realise the benefit of the ITC. During this waiting period, the accrued dollar benefit of the ITC must effectively be financed by some other means, which renders the ITC less useful than an equivalent up-front cash rebate; In this light, it is worth noting that the idea of temporarily (i.e. for projects completed in 2009 and 2010 only) giving taxpayers a choice between the existing ITC or a cash grant of equivalent value (to be disbursed within 60 days of project completion) has been included in an early version of the much-anticipated “stimulus bill” currently being debated by Congress;
  • With the US$2,000 cap removed, the uncapped ITC may be too large for some taxpayers to absorb in the first year, or perhaps ever (in the most extreme cases). Although any unused portion of the credit can be rolled forward at least through 2016, doing so reduces the value of the credit in current dollars; Again, the grant program proposed in an early version of the stimulus bill (and described in the previous bullet) would address this issue, as would a “refundable” ITC, which has also been discussed (i.e., if the taxpayer cannot make use of some or all of the credit in the year it is generated, the government would refund the difference via a cash payment);
  • In recent years, the PV market in the US has been increasingly dominated by the commercial sector. Maintaining the status quo on residential rebate levels, or reducing them by less is possible, and may help to restore more of a balance between the residential and commercial markets;
  • Somewhat related, figure 1 assumes that current rebate levels are set at the “correct” level to provide the desired amount of support for the residential sector. If instead current residential rebate levels are too low to adequately stimulate desired market demand, then the results shown in figure 1 may be too aggressive.
  • Finally, leaving residential rebate levels unchanged should accelerate the adoption of residential PV at no extra per-system cost to the programme. This motivation, however, must be weighed against the foregone benefit of any additional installations that could be supported by reducing rebate levels – and thereby stretching fixed programme budgets further.

Why could subsidised loan programmes lose their lustre?

A number of State and local Government agencies offer low-interest loan programmes to help finance the installation of PV systems. Although these programmes can ease the burden of purchasing a PV system, if the Internal Revenue Service considers such a loan to be “subsidised energy financing,” then the 30% ITC will only apply to the portion of installed project costs not financed by the loan.

With the residential ITC capped at just US$2,000, the reduction or loss of the ITC due to the use of subsidised energy financing has – up to this point – not necessarily been a losing proposition. Depending on the specifics of the programme, attractive financing terms may actually outweigh the loss of the capped ITC. This is particularly true for larger residential PV systems, where the capped ITC represents a smaller proportion of the overall costs that need to be financed.

Now that the cap has been lifted, however, much more economic value is at stake. A 4 kW system installed at US$8.5/W and receiving a US$3/W rebate will now be eligible for an ITC of either US$10,200 or US$6,600, depending on whether or not the rebate is taxable. The loss of this amount of tax credit value (or some fraction thereof, if only a portion or the system is financed through such a programme) will obviously impinge upon system economics much more than the loss of just US$2,000, and is likely to make even the most aggressive low-interest loan programmes uneconomical.

Although low-interest loan programmes may continue to fill an important need for those residents who are unable to make efficient use of the uncapped ITC, it is now more important than ever to understand whether such programmes are at risk of being considered “subsidised energy financing,” and to take steps to minimise the potential for such a characterisation. Finally, it is worth noting that an early version of the stimulus bill currently being debated by Congress eliminates this “anti-double-dipping” provision altogether, which (if ultimately signed into law) would allow projects to benefit from both subsidised financing and the ITC without any of the negative consequences described above.

Third-party ownership structures may still have potential

For several years now, the non-residential sector in the USA has benefited from third-party PV financing structures, including leasing and power purchase agreements (PPAs), that enable site hosts to “go solar” without the associated up-front costs and, in some cases, risks of ownership. By engaging “tax equity” investors with an appetite for tax credits, these third-party ownership structures also enable the efficient use of the substantial tax benefits (including the commercial ITC and accelerated tax depreciation) provided to a commercial PV project.

Because commercial PV projects have historically received greater tax benefits than residential systems, one would think that – other potential benefits aside – the ability to monetise and pass along these greater tax benefits would have made the residential sector a particularly attractive market for commercial third-party ownership. Yet, due to a combination of heightened credit concerns, larger proportional transaction costs, and a simple need to first gain comfort with the structures in a commercial setting, third-party ownership has been somewhat slower in coming to the residential sector than to the commercial sector.

Within the past year, however, several PV installers have begun to offer third-party leases and PPAs to the residential sector. Just as these offerings have begun to make inroads, however, the elimination of the US$2,000 residential ITC cap starting in 2009 has removed a major advantage of these third-party ownership structures in the residential sector. Specifically, going forward, commercial and residential systems will be on roughly equal footing from a tax perspective, each receiving net tax benefits equal to about 30% of the installed costs on a present value basis.

The loss of this tax-based arbitrage opportunity, however, does not necessarily sound the death knell for third-party ownership in the residential sector. As discussed earlier, with state and local PV programmes reducing their residential rebate levels in response to the ITC revisions, system owners having to wait up to a year or more to realise the tax benefits of the ITC, and “subsidised” financing programmes no longer making much sense for PV, there are likely to be fewer financing options available to cash-strapped prospective PV owners. This could potentially create a greater need for third-party ownership than currently exists. Furthermore, third-party ownership provides other potentially attractive benefits besides tax credit monetisation (e.g., no performance risk), which may continue to provide a compelling rationale for third-party ownership of residential PV systems.

At the same time, however, many of the tax equity investors that have traditionally financed these third-party-owned projects – i.e. large banks and insurance companies – have withdrawn from the PV market as their need to shelter taxable income has disappeared along with their profits, amidst the global financial crisis. Furthermore, if some of the changes to the ITC proposed in early versions of the stimulus package (and described above) come to fruition – e.g. making the credit refundable, or exchanging it altogether for a cash grant of equivalent value – then the need for third-party ownership in the residential sector will likely diminish further.


Although policy support for emerging technologies generally seeks to reward early adopters, in the case of the residential ITC, procrastinators have been the beneficiaries – initially in 2006 when the capped ITC was first implemented, 2008 when the US$2,000 cap was eventually lifted – starting in 2009, and perhaps once again in 2009 as a result of the impending stimulus package, remains to be seen. Though welcomed by the industry and prospective PV owners, these changes in federal tax policy have required reactive planning at the state and local levels.


About this article
This article is adapted from a longer Berkeley Lab report entitled “Shaking Up the Residential PV Market: Implications of Recent Changes to the ITC” and available at http://eetd.lbl.gov/EA/EMP/cases/res-itc-report.pdf.This work was funded by the Clean Energy States Alliance, and by the US Department of Energy (the Office of Energy Efficiency and Renewable Energy, Solar Energy Technologies Program, as well as the Office of Electricity Delivery and Energy Reliability, Permitting, Siting and Analysis) under Contract No. DE-AC02-05CH11231.


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