While the greenest air conditioning system is no air conditioning system, in some parts of the control, central air is necessary during the summer. Air conditioning systems can be real electricity guzzlers, but there are ways to improve the efficiency of your air conditioning system.

On a basic level, make sure that your air conditioning system is the right size for the space it needs to cool. The output of an air conditioning system is measured by the ton, and residential units are usually between one and five tons. It’s not uncommon for HVAC contractors to install a more powerful air conditioning unit than is strictly necessary. The house stays cool, but the AC burns more power than it really needs to. And in a similar “more is not necessarily more” vein, determine if you need air conditioning for an entire home or building, or just a few rooms. If air conditioning is only necessary in a few rooms, window AC units are more economical and will use less energy.

It’s also important to make sure that you are using an environmentally friendly refrigerant. Air conditioning units have, for the most part, used R22, also known as freon. R22 contributes to the depletion of the ozone layer, and since 2010 it is no longer allowed for use in new air conditioning systems, although older air conditioning systems that use R22 can be replenished. It is also less efficient then its replacement, R-410A, also known as Puron, which does not contribute to the depletion of the ozone layer. R-410A can not be used by a system that was built for use of R22. If you have an old system that’s running on R22, consider that the savings from the increased efficiency of a newer system that uses R-410A will at least somewhat offset the initial cost of installing new air conditioning.

Passive cooling, natural ventilation, and other design elements can decrease or eliminate the need for an HVAC system, but energy efficient air conditioning is a green and often necessary option.

SB 100, a bill that mandates that the state will receive all its power from sources that do not produce carbon emissions by the year 2045, came one step closer to becoming a law, or at least landing on Gov. Jerry Brown’s desk. The bill cleared two important hurdles in Sacramento this month, passing both the Assembly Natural Resources Committee and the Assembly Utilities and Energy Committee.

If the bill becomes law, California utilities would be required to get 50 percent of electricity from clean sources by 2026, four years earlier than currently required by law. By 2030, that number jumps up to sixty percent, and by 2045, there would be no electricity generated from fossil fuels in the state of California. Essentially, SB 100 is an acceleration of the state’s existing renewable energy program, Renewables Portfolio Standard (RPS). The RPS has proven to be a driver of renewable energy development, as well the reduction of greenhouse gas emissions and air pollution.

Under SB 100, nuclear power and utility-scale hydropower count as clean energy. The utilities have not offered strong opposition to the bill, with some pledging their support.

While this might seem incredibly ambitious – a hundred percent is a striking figure to read when it comes renewable energy – for a sense of perspective, look back twenty-eight years. In 1989, renewable energy was in its nascent stages. Looking at how far clean power has come since then, is it so crazy to think that California could run on 100% clean power in another twenty-eight years?

When the federal government drops the ball on climate change, California is eager to step up to the plate. From fighting for the Clean Air Act Waiver to aiming for 100 percent renewable energy by 2045, California lawmakers are embracing their state’s role in leading the nation on green energy policy. The federal government provides a federal tax credit of up to $7,500, but that will be phased out by manufacturer as each car maker sells 200,000 plug-in vehicles.

Assembly Bill 1184 aims to make up for the loss of the federal tax credit for electric cars in the hopes of getting more Californians behind the wheel of an electric car. The bill would provide point of sale rebates for electric cars, with the tax credit allocated based on the buyer’s income. The rebates would be phased out as natural demand rises and the electric car market stabilizes, or by 2030.

California has spent $430 million on low-emission vehicles subsidies over the past seven years, and Assembly Bill 1184 would extend that program for another seven years, but at a cost of $3 billion dollars. Rebates are currently funded by California’s cap-and-trade system, an arguably unreliable source of funding, and as of June 30th, the state’s electric car subsidy fund is broke. Once the fund runs out of money, buyers are put on a waiting list. AB 1184 aims to provide a stable source of funding to make rebates available throughout the year, with a plan based on an incentive structure the state using for solar panels.

Electric cars have gone from a fringe, impractical alternative to gas-powered vehicles, to an expensive status symbol, to a more accessible, affordable car. The Chevy Bolt, Nissan Leaf, and the new, mid-market Tesla Model 3 have made owning an electric car a more viable option for middle class Californians. Sales of electric cars rose ninety-one percent in the first quarter of 2017 from the same period last year. While electric cars still only account for 2.7% share of the cars and light trucks market -13,804 pure electric vehicles were sold out of the total 506,745 cars and light trucks sold in the first quarter of the year, with Tesla and Chevrolet accounting for most of the electric cars sold – California alone accounts for roughly 50% of all electric cars sold in the US.

Researchers at UC Berkeley and Berkeley Law, in a study commissioned by the nonprofit Next 10, found that California’s efforts to fight climate change added 41,000 jobs and $9.1 billion to the Inland Empire’s economy from 2010-2016. Many of these jobs were construction jobs that came from one-time construction investments in building renewable energy power plants. When accounting for the ripple effects of this economic activity, the researchers found that state climate change policies had resulted in $14.2 billion dollars in economic activity and 73,000 jobs in the region over the same period.

The researchers chose to study the Inland Empire, defined in this study as San Bernadino and Riverside counties, due to the unique environmental challenges the region faces. The Inland Empire has long been a hub for the transportation of people – bedroom community commuters spending hours on the freeway – and consumer goods. The region’s proximity to Los Angeles as well as the Inland Empire’s warehouse, logistics, and manufacturing activity combined with the region’s geography have come at an environmental cost. San Bernadino and Riverside counties consistently have the worst smog in the state, and Inland Empire residents are at greater risk for air-pollution related health problems.

The Inland Empire also faces economic challenges. The Inland Empire is one of the lowest-earning metropolitan areas in California, with over 17.5 percent of the region’s population living below the federal poverty line in 2015, compared to the overall 14.7 percent of California residents. The fragile environment and economy of San Bernadino and Riverside counties make the Inland Empire an important region in which to study the economic impact of California’s efforts to fight climate change.

The report makes a quantitative assessment of the economic impacts of four of California’s major climate programs and policies – cap and trade, the renewables portfolio standard (RPS), distributed solar programs, and invester-owned utility – and concludes that climate change policies have had a net positive economic effect on the region. There is still plenty of room for improvement, however, and the report makes several policy recommendations that range from creating a comprehensive program for transportation to developing programs that can help workers transition out of jobs greenhouse gas-emitting industries.

While some GOP lawmakers in the House and Senate wanted to kill federal subsidies for electric vehicles, wind, and solar power, the final version of the tax bill keeps the wind Production Tax Credit (PTC), the solar Investment Tax Credit (ITC), and the electric vehicle tax credit. The bill does kill the nuclear and “other” technology credits (geothermal, for example), and may reduce the tax equity value of the wind and solar credits.

Tax equity is the main financing tool for wind and solar projects, making up to forty to fifty percent of the funds for the average solar project and fifty to sixty percent of the funds for the average wind farm. The reduction of the corporate tax rate also means that there is less tax equity to use for renewable energy projects.

The Base Erosion Anti-Abuse Tax (BEAT) initially made the renewable energy sector very, very nervous, but a fix to that in the final version of the bill has many breathing a cautious sigh of relief. Essentially, the BEAT provision would require multinational companies to have two calculations of their taxes owed, one based on ten percent of a companies taxable income, and the other determining tax liability minus any tax credits, such as those from renewable energy. Multinational corporations would have been required to pay the difference if one figure ends up lower than the other, and this provision would have essentially eliminated tax incentives for investing in renewable energy. However, in the final version of the bill, energy companies will be able to offset eighty percent of that tax. This amendment, however, only lasts until 2025.

Beyond the loss of the “other” renewable energy credits for geothermal, nuclear, and other sources of energy, the main concern with the final version of the tax bill is that it will make the math for renewable energy tax credits more complicated and less attractive to energy companies. Moreover, the bill is also a huge boon to the oil, coal, and gas industries, who hailed the lower corporate tax rate as a victory. The bill also includes a controversial provision to allow oil drilling in the Alaskan Arctic National Wildlife Refuge (AANWR), a move hailed by Alaskan Senator Lisa Murkowski as an important step for US energy independence, while environmentalists counter that drilling in AANWR will do irreparable damage to wildlife and millions of acres of wilderness.

Carbon is the leading cause of global climate change, and carbon pricing offers a tangible, financial penalty greenhouse gas emissions. According to many economists, climate change is a “market failure.”Society at large bears the cost of emitting CO2, while the polluters accrue the benefits.

The EPA and other government agencies use estimates of the social cost of carbon (SC-CO2), a dollar value given to measure the long term damage caused by of a ton of carbon in a year, to weigh the potential economic effects of climate change and climate change policy. SC-CO2 is intended to be a fully comprehensive measure of the economic effects of greenhouse gas emissions, and includes changes in net agricultural productivity, human health, property damage, and changes in energy system costs, but the predicted changes are, some argue, missing crucial information due to the lack of information and research on the precise nature of the damage from climate change.

A March, 2017 executive order from President Trump took on the social cost of carbon. The executive order returns to using data from 2003 to calculate SC-CO2, and disbands the non-partisan group of scientists who estimate SC-CO2.

The two main types of policies use throughout the world to create a financial penalty for greenhouse emissions are a carbon tax and cap and trade. Both cap and trade and a carbon tax encourage the lowest cost emission reductions, generate government revenue, and provide an incentive for investors and entrepreneurs to develop low-carbon technologies.

A carbon tax creates a stable, direct price on greenhouse gas emissions, whereas a cap and trade policy establishes an emissions cap, or a set number of allowances of production of greenhouse gases each year. The carbon tax essentially sets the price of emissions and lets the market decide the emission reductions, whereas cap and trade sets the standard for emissions reductions and lets the market react. Both policies have their share of advantages and disadvantages, but cap and trade is arguably a favorite among environmental policy-makers while energy companies are usually on the record as preferring a carbon tax.

California has had a cap and trade program in place since 2013, and it is the fourth largest in the world. The state’s emissions trading system is projected to reduce greenhouse gas emissions from regulated carbon producers by at least 16 percent by the year 2020, and an additional 40 percent by the year 2030. 450 business responsible for 85 percent of the state’s greenhouse gas emissions are required to comply with the program.