Construction was down, but green building wasn't entirely out. Developers reported that green buildings garnered higher rents than conventional ones. The State of California and the Federal Government also committed billions to retrofits. Here are some of the big stories and events from the year:

1. A Green Building Overview: One of the more intriguing articles on the green building landscape this year, at least according to the author.

2. The Big Dimmer: Adura Technologies and Lumenergi marketed systems to dim fluorescent bulbs, those energy-gobbling things right above your head. Both have shown how power going into lights can be trimmed by 70 percent plus without the occupants freaking out. (Lighting consumes 22 percent of the power in America and a lot of it gets wasted or dispersed indiscriminately.) These sort of systems can ultimately be ported to light emitting diodes and heating/air conditioning systems. Other building management companies to watch: EcoFactor, Tendril, and EnerNoc.

Some of the control freaks listed above could make a lot of money.

Speaking of lights, LED lights dropped in price and bulb equivalent units may cost $25 in a few years, bringing the payback to a little over a year. Regulations in any event will encourage adoption (see Road Map to New Lighting for more).

3. PACE Picks up the Pace: Property assessed clean energy loans (PACE) went from an obscure acronym in the green building market to a popular policy initiative championed by several states and Vice President Joe Biden in less than a year. In Pace loans, the money gets paid back through supplemental property tax assessments. That small twist brings a host of benefits. The owner doesn't have to worry about losing the value of any retrofit if the home gets sold because the new owner assumes the payments. The payments, ideally, can also be lower than the amount saved on energy bills, making the retrofits free. Local communities see job activity in the area and moribund banks get to write loans.

Fourteen states including Florida, Texas and Maryland as well as 30 municipalities have already passed PACE programs. Berkeley, Calif. became the first governmental body to issue PACE bonds in January. Renewable Finance, founded by PACE co-creator Cisco DeVries, got $12.2 million in VC funds.

4. Green Building Materials Still Coming: Serious Materials, the green drywall guys, raised $60 million more and went to the White House. A legion of other companies – Aspen Aerogels, Integrity Block, Calstar Products, Arrx, E2E Materials – became more visible too. But the market still mostly exists in theory rather than fact. Calstar just started putting out its bricks.

5. The Big Green Market – Schools: Schools have received billions in stimulus dollars to retrofit for energy efficiency. Just as important, they don't suffer from the split responsibility problem that can often hurt commercial buildings: the owner and tenant are the same person. Limbach Energy Solutions is taking a school retrofit program that pays for improvements out of energy efficiency used in Ohio nationwide.

Homeowners didn't get shorted either. California has earmarked $3.1 billion for energy efficiency retrofits over the next three years and a lot of that money will get spent in the form of rebates from utilities. Help may come on the federal level too. Matt Golden of Recurve (formerly Sustainable Spaces) is one of the people behind a Cash for Caulkers retrofit and job creation program being circulated in Washington.

6. Air Conditioners Get Hip: Unless you're a charter member of ASHRAE, you don't think about air conditioning too much. That's changing and a host of new technologies are on the the way. AC consumes a lot of power and people in offices often complain about frigid offices in summertime. Some policy makers and utilities have also begun to contemplate programs under which utilities would pay customers to swap out old systems for new ones powered by ice that don't require much peak power.

7. Skyscrapers and China Go Green: $20 million for things like 6,500 thermal windows will result in energy savings worth up to $4.4 million a year. If you turned that into pennies and threw them off the observation deck, well, let's not think about the consequences.

Another interesting project: The Shanghai Center, destined to become the world' second largest building, will consist of neighborhood stacked on top of each other complete with "open air" parks.

8. Cavemen: The New Thought Leaders. Did you know there is some archaeological evidence that caves were in part selected for their lighting? Neither did I and I prefer not to delve too deeply into finding out whether it's true or not.  I prefer to believe. In any event, passive design techniques-harmonizing a building with its surroundings-continues to gain credence. Alcoa and its Kawneer division, among others, began to more actively promote two products for passive control: light shelves (i.e., white boards that reflect sunlight in) and operable windows (i.e., windows that open).

"You used to build skyscrapers like aquariums. Now we realize that there are a lot of good things outside," said Eddie Bugg, director of sustainable solutions at Kawneer. "Twenty years ago, [owners] never wanted operable windows. Now we are seeing more and more installed.

Ohlone College, meanwhile, installed enthalpy machines that can pre-cool or pre-heat air from the outside (depending on the time of year) with the energy in the indoor air to cut down the power needed for the ventilation system.

9. TVs Go Green in California: We include TVs here because electronics consume about 8 percent of the energy consumes in U.S. homes. Computers only account for 1 percent. The California Energy Commission passed regulations that will force TV makers to reduce power consumption by 33 percent by 2011 and 49 percent by 2013. It was a long, hard-fought battle. Ontario and other places may follow.

10. Net Zero Looks Doable: When the State of California said it wanted to see all new homes become net zero structures by 2020 and commercial buildings to follow by 2030, many guffawed. But Zeta Communities built a net zero prototype in Oakland and Project Frog is building an energy efficient warming hut on San Francisco's Crissy Field. The U.S. Army commissioned net-zero duplexes for one of its bases in December.

Photo via Zeta Communities.

Tags: adura, air conditioning, alcoa, arra, bentley systems, california energy commission, empire state building, energy efficiency, green building, ice bear, integrity block, led lights, limbach, lumenergi, marc porat