Wednesday, April 25, 2007

Solar Roof Programs - I


Mass-production drives down per-unit costs. This is true even with energy, so driving an electric car running on power mass-produced at a huge power plant is more efficient that running your IC-engine car where the power is produced by a relatively tiny 2 liter engine.

However one form of energy that does not gain from mass-production is solar photo-voltaic power. Thats because a given solar cell will produce the same amount of power whether it is placed in isolation or with a million other such cells.

This presents some unique opportunities for those working to popularize solar power. Since mass-production offers no advantages it makes sense to promote individual installations in homes for a variety of reasons.

#1 - Production at point of Consumption

The power is produced right where it is needed, eliminating transmission and distribution (T&D) losses. So if 1 kW of power is generated, most of it is used.

#2 - Reduced Infrastructure Costs

The expensive and elaborate T&D infrastructure is not used. This reduces load on the infrastructure where it exists, and obviates the need for it where it does not. Thus remote regions can get powered without the need to set up and maintain expensive transmission lines. The fact that they are remote usually makes the set-up even more expensive.

#3 - Serve the niche market without affecting the mass market

Solar PV is still rather expensive from a capital cost perspective, so that restricts the commercial viability of a large plant. Thats because a commercial plant has to sell power to the rich alt-e enthusiasts and the poor at the same rates.

This however does not stop very small scale installations like in residences. The extra cost is made up for in part by the government via subsidies, and in part by the people installing it themselves. Thus the market for solar PV power, usually relatively wealthy solar power enthusiasts, is satisfied without taxing the relatively poor.

So the obvious answer is...

The third point is probably the most significant, and is driving "solar roof" installations in developed countries. A solar roof usually means installing solar panels (or solar shingles or solar tiles, or any other type of solar PV roofing material) on the roof of an individual house or residential system. The average solar roof should have a rating of 3 kW to source the power requirements of the residential unit.

* The earliest solar roof program was launched by Japan back in 1994. It was a 70,000 roof program which reached 144,000 roofs in 2002.
* In 1997, President Clinton launched a national Million Solar Roof Initiative in the US, which without any formal budget still reached 229,000 installations by 2003.
* Germany has had great success with its Solar Roof efforts ramping up from an initial 1000 solar roof program to a 100,000 solar roof program, in 1998. This program met its target in 2003 with 3 years to spare.
* Probably the most ambitious of all current programs is the California Million Solar Roofs Plan (CMSRP). With this California alone aims to create 3000 MW of solar power capacity in 10 years. To put that in perspective Governor Schwarzenegger wants California to achieve in 10 years in one state, what President Clinton aimed to achieve in 50 states in 13 years.

Despite the ambitious nature of the CMSRP, it would seem to have a much better chance of success than the Clinton initiative. There are two reasons:
1. The economic and political costs of oil have sky-rocketed, ensuring a very wide range of support for alternate energy.
2. The costs of alternate energy have fallen. Solar modules cost $5 per watt in 1998. The cheapest thin-film module retails for $3 per watt today.

Neither of these look like they will change in the near future. The CMSRP does face serious challenges, but the lessons learnt will encourage more states in the US to launch similar programs. In the near future, as solar power gets cheap enough developing countries will have their own such programs, and before long we will see the advent of commercial solar power stations that are cost competitive with coal. Towards that goal does the promise of solar power lead us.