Swine and poultry are the major types of livestock. Horses are kept for draft purposes, primarily by farmers working their ʻapi ʻuta (a plot of bushland). More cattle are being raised, and beef imports are declining. The traditional feudal land ownership system meant that farmers had no incentive to invest in planting long-term tree crops on land they did not own. In the late 20th century, kava and vanilla from larger plantations became the main agricultural exports, together with squash. The export of squash to Japan, beginning in 1987, once brought relief to Tonga's struggling economy, but local farmers became increasingly wary of the Japanese market due to price fluctuations, and the huge financial risks involved. Energy Energy in Tonga mostly comes from imported diesel. Energy consumption in Tonga is projected to reach around 66 gigawatt hours by 2020. The country aimed to reach 50% of renewable energy by 2020. In 2019, Tonga announced the construction of a 6-megawatt solar farm on Tongatapu. The plant will be the second-largest solar plant in the Pacific upon completion. In view of the decreasing reliability of fossil-fuel electricity generation, its increasing costs, and negative environmental side effects, renewable energy solutions have attracted the government's attention. Together with IRENA, Tonga has planned a renewable energy based strategy to power the main and outer islands. The strategy focuses on solar home systems that turn individual households into small power plants. It calls for the involvement of local operators, finance institutions, and technicians to provide sustainable business models and strategies to ensure the effective operation, management, and maintenance once the systems are installed. The Pacific Centre for Renewable Energy and Energy Efficiency was established in Tonga in 2016 to advise the private sector on related policy matters, provide capacity development and promote business investment. The centre facilitates a financial mechanism offering competitive grants for start-ups to spur the adoption of renewable energy by the business sector. The centre is part of the Global Network of Regional Sustainable Energy Centres and SIDS DOCK framework designed to attract international investment in the renewable energy sector. With the assistance of IRENA, Tonga has developed the 2010–2020 Tonga Energy Road Map, which aims for a 50% reduction of diesel importation. This was to be accomplished through a range of appropriate renewable technologies, including wind and solar, as well as innovative efficiencies. As of 2018, Tonga was generating 10% of its