You can't logically ignore the capital costs of solar and wind. Both are around $3/watt and work only 20% of time so you need $15/watt. You lose atleast 20% energy during the most efficient storage (batteries) so the cost is $18.75/watt. Then add the maintenance cost which would be atleast 12.5% of the capital cost, so the total cost is %21/watt. Then add the cost of the battery which would be atleast 12.5% of the cost above. This takes the total cost to about $24/watt.

This system work for 30 years before total replacement and produce:

30 years x 365 days/year x 86400 second/day = 947 MJ energy

Each one dollar in gdp consumes 10 MJ energy (divide world/country/province gdp by world/country/province energy consumption) so each watt capacity above contributes $94.7 over a period of 30 years.

This is a ROI of less than 400% in 30 years or a linear 13.16%/year or an exponential 5%/year. Thats ROI in overall GDP of country. Given that each barrel of oil contributes about $600 in gdp and maximum per barrel oil price in history is $150 which is 25% of its contribution in gdp we can assume that the owner of solar cells or wind mill will only get at maximum 3.25% linear ROI per year.

In hot areas it has even been found that people are prepared to pay enough for shaded parking that it can pay for a solar covering to the car park!

A great example of how limited our predictions for the future can be. Perhaps it has been mentioned before on TOD but I, like many others I'm betting, had typically thought of EVs being recharged at home because the recharging cycle could be scheduled for off peak generation. Recharging during working hours has its problems in stressing the electric grid and peak generation capacity.

Solar generated electric has a long way to go with regards to cost per watt. (I think that is the measure:) Home solar is still a niche market and more of a good faith effort to move solar forward than to save money. By taking advantage of the commercial scale of solar installation and integrating it into the company's workplace as either a cost free benefit (perhaps the IRS would be willing to not tax the value of that benefit:) or a low cost benefit that helps to subsidize the installation costs is a win win situation. Not to mention a huge shot in the arm for the solar industry.

Let's take it one step further and consider the problem of compressed natural gas replacing a significant portion of gasoline usage. That problem being distribution of refueling facilities. Let's put in natural gas fueling facilities on company parking lots. Again, you have the advantage of scale (if the number of work vehicles is large enough). It will be a balancing act between the number of pumps vs the number of vehicles and how many need to fuel up each day. Still, think of the huge number of gas stations throughout the country that don't have the customer volume to add natural gas. Medium to large companies can help considerably in achieving the critical mass of fueling stations for natural gas to take off.

The thought of using canopies as a dual system to reduce heat buildup in cars and as a platform for solar panels solves the not insignificant problem of protecting the users of a charging station from being electrocuted during a rain storm. You also solve the square footage limitation on company building rooftops to install solar panels on.

I don't want to imply this is a done deal. I'm saying there are a significant number of ways to think a bit outside the box and some will be home runs. Leaving many of us to slap our heads and say "why didn't I think of that!"

Hmm, parking garages?