The U.K. government is mulling over whether to cut another solar subsidy — this time for farmers who use a portion of their land to generate clean energy — in another massive blow to the British solar industry, following the disastrous feed-in-tariff reversal.

Meanwhile, in the U.S. subsidies are alive, well and behind an impressive 418 percent growth in solar capacity over the last four years.

Equally, solar uptake is unevenly distributed in the States, in a pattern that reflects local lawmakers' attitudes. Despite being the Sunshine State, Florida has far less solar than the milder Northeast — more solar panels are in New York state than yellow cabs are in New York City.

The U.K. would do well to learn this lesson. Projections are that as the price of solar falls, economics will take over and the sector will grow on its own, but state subsidies are playing a highly significant role in getting there.

But solar still only accounts for a deeply unimpressive 1.13 percent of U.S. power generation, whereas the U.K. has reached short-term heights of 7.8 percent over the summer. What else can we learn from our cousins across the pond? And what can we teach them?

Double-cropping land

Environment Secretary Liz Truss' reasoning behind cutting farmers' solar subsidy is twofold: that the panels are a “blight” on the landscape — the classic NIMBY defense of England's green and pleasant land — and that they take up valuable farming space that otherwise could be used for food.

The U.K. has form in “double-cropping” land. Green energy provider Ecotricity has a solar farm that is also planted with wildflowers to attract bees. But the U.S. is leading the way here. A project in Piedmont, Calif., is using the same land to harness solar energy and plant shade-loving crops underneath, so no land is lost to food production.

Solar car parks

Both the U.K. and U.S. boast quite a few solar car parks, where panels double as electricity generation and shade for cars — but a more fascinating project is being developed with support from the Federal Highway Administration that shows just how much potential there is in the double use of land.

The Solar Roadways project recently has completed a prototype solar parking lot, which consists of a road surface constructed out of solar panels. The idea is to scale up to replacing tarmac roads with solar roadways. The electricity generated eventually would pay for its own construction. Energy collected can be used to heat the panels to prevent snow and ice. Eventually the panels could be used to power electric vehicles so they can recharge wherever they are.

Mass-scale solar farms

The Ivanpah solar farm in the Mojave Desert is largest in the world. It's designed to power 140,000 homes by generating up to 400 megawatts of energy from a single location. To underline the importance of state subsidy, its construction was based on a $1.6 billion federal grant.

Solar farms can be a double-edge sword.

However, not all is well in the Mojave. Firstly, the environmental impact has not been entirely positive. In particular, birds are attracted to the farm — a glinting oasis in the desert — only to be summarily fried when they reach it. The panels are killing wildlife.

Secondly, critics point out that thanks to the lead-time in a fast-moving sector, the farm is already technologically outdated, making the electricity it generates relatively expensive. That's not to say mass farms can't be useful in the future, but while development is rapid, perhaps it's best to stay small scale.

British Gas community solar

A very interesting project that's emerged in the U.K. is the British Gas community solar project. The largest energy provider in the country is backing a $94 million project putting solar panels on the roofs of public buildings such as schools, offering local communities the chance to invest in the panels (and the proceeds of electricity generated).

Although this is another example of canny use of space — the U.K. doesn't have desert space like the U.S. — the key lesson for America here is for the energy companies. The main complaint of clean energy supporters is the fossil fuel lobby standing in the way of the transition to solar, hydro and wind. Understandably, as it represents the hollowing out of their existing market, and changing energy sources requires massive investment.

But the price of solar is already falling dramatically and is very close to matching the price of fossil fuel energy in the wholesale market — at which point market economics will take over. Big Energy is spitting in the wind. By backing this project, British Gas is demonstrating long-term business savvy that American energy companies would do well to emulate before they become fossils themselves.

This is an exciting time for solar energy, with remarkable innovation on both sides of the pond. It's also a critical time for the development of both technology and market, both of which require government support if we're to reap the long-term benefits.